# ClinicalTrials.gov Search

> ClinicalTrials.gov Search is a paid API for AI agents from agents.crowdspark.me, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-31).

Searches ClinicalTrials.gov for clinical studies by keyword, condition, or intervention, returning structured trial metadata including NCT ID, status, phases, enrollment, sponsors, and site counts.

## Facts

- Endpoint: GET https://agents.crowdspark.me/v1/gov/clinical-trials?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/clinicaltrials-gov-search-4cdac6d7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_F8ooaXXe3tsGgxNtTaKBt

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability clinicaltrials-gov-search-4cdac6d7
```

Example prompt: Search ClinicalTrials.gov for recruiting Phase 2 or Phase 3 trials studying semaglutide for obesity — give me up to 15 results with their NCT IDs, enrollment numbers, and sponsor names.

## When to prefer this

Use this endpoint when you need structured, queryable data from the official ClinicalTrials.gov registry — especially when you need to filter by recruitment status, phase, condition, intervention, or geography. Prefer this over general web search when you need machine-readable fields like NCT ID, enrollment, sponsor, and completion dates for downstream processing, reporting, or patient-matching workflows.

## Known failure modes

- No trials found for highly specific or obscure query terms — returns empty studies array
- Invalid phase or status enum values may be ignored or return unexpected results
- Location filtering may not match all site countries if location string is ambiguous
- Limit exceeding 25 is clamped or rejected
- Free-text queries with typos or brand names instead of generic drug names may miss results
- Rate limit exceeded if daily free-tier quota exhausted without payment header

## How this service works

Pay-per-call utilities for AI agents over x402, USDC on Base.

## Output

A JSON object with a list of up to 25 matching studies, each containing NCT ID, title, status, phases, study type, enrollment count, conditions, interventions, lead sponsor, start and completion dates, a boolean results flag, site count, and a direct link to the trial on ClinicalTrials.gov. Also includes total match count, number returned, source attribution, and a disclaimer that data is from the public registry and not medical advice.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "q": {
       "type": "string",
       "description": "Optional free-text term"
      },
      "limit": {
       "type": "string",
       "description": "1 to 25, default 10"
      },
      "phase": {
       "type": "string",
       "description": "Optional phase or comma list, e.g. PHASE2,PHASE3"
      },
      "status": {
       "type": "string",
       "description": "Optional status or comma list, e.g. RECRUITING"
      },
      "location": {
       "type": "string",
       "description": "Optional city, state or country"
      },
      "condition": {
       "type": "string",
       "description": "Optional condition or disease"
      },
      "intervention": {
       "type": "string",
       "description": "Optional drug, device or procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "source": "ClinicalTrials.gov API v2 (US NLM, public)",
  "studies": [
   {
    "url": "https://clinicaltrials.gov/study/NCT06467604",
    "title": "CRAVE Study: Comparing Craving Responses and Diet Quality of GLP1 Receptor Agonist Users",
    "nct_id": "NCT06467604",
    "phases": [
     "NA"
    ],
    "status": "ACTIVE_NOT_RECRUITING",
    "sponsor": "University of California, Davis",
    "conditions": [
     "Obesity"
    ],
    "enrollment": 60,
    "start_date": "2024-11-01",
    "study_type": "OBSERVATIONAL",
    "has_results": false,
    "interventions": [],
    "completion_date": null,
    "locations_count": 1
   }
  ],
  "returned": 1,
  "disclaimer": "Registry data only. Not medical advice.",
  "total_matches": 822
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/clinicaltrials-gov-search-4cdac6d7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agents.crowdspark.me](https://www.zero.xyz/host/agents.crowdspark.me/llms.txt)